Moderator Effectiveness Test

[scratchcoobster]

Don't know where this should be posted so I put it here. Thought it would be of more value to PCP shooters than others. Thought it might get lost in "Other Accessories and Equipment".

I was able to get together 6 different moderators to test sound reduction when firing my air gun. These covered a range of lengths, weights, diameters and manufacturers that is only a tiny part of what is available on the market, but should give some indication of the effectiveness of moderators in a general sense.

This test was not meant to be exhaustive or scientifically accurate and only reflects my findings, in my surroundings with my combination of equipment. Your results may certainly vary, but I found this interesting and hope it can provide some insight and information to other users.

The following table gives the Moderator specs, the Avg dB reading for each, and the Reduction (in dB) from the un-moderated air gun.

Moderators Tested and Results:





Note: The FX OEM Moderator came with the FX Crown and is an empty can.

The 0dB Silencer moderators have no Model, so I labeled them as short and long.

The DonnyFL FX is a DonnyFL designed/licensed moderator made for the FX.

Moderators were .25 Cal.

Air Gun was a Daystate Red Wolf Safari HP, Carbon Fiber Shroud, .22 Cal

Pellet was JSB 25.39 gr RD Monster .22 Cal.

All Readings were taken with a dB Sound Meter (NOT phone app) at 1 foot from muzzle.

No wind, 5,000 ft altitude, 90 degrees F, 15% humidity, BP 30.06

Five shots were fired through each moderator to achieve an average reading.

The Reduction value was calculated from the un-moderated sound level of the air gun shooting the above mentioned pellets (Avg. 87.5 dB).

As you can see, the reduction (or dB Drop) varies from less than 1 dB to almost 2 dB across moderators on average. A 1 dB drop is indicating an approximate 21% reduction of sound, with 79% of the sound surviving. 

As a quick comparison test I tried 3 moderators on a .25 cal Brocock Sniper with an un-moderated sound level of 94.8 dB. Appreciably more than the well shrouded Red wolf's 87.5 dB. The moderators were more effective with reducing the sound level from the louder gun. On average the reduction was 5 to 10 dB. Need to do some more testing on this and finalize my results.

 

[Yo]

Different results for different guns for sure.

 

[BlackICE]

I don't know what type of sound meter your using but most do not pick up Peak values. They just pick up an average which is not representative of what a person would hear. I use audyssey program on a PC 2 gauge relative loudness of the sounds. Since the microphone on a PC is crap you can assume it's not linear and it's loudness response and it isn't flat in his frequency response either. However it does pick up the actual sound waveform so you can pick up Peaks very easily and you can compare them against other tests. Unless you are testing in the middle of a desert then you have to consider attenuation and Reflections from nearby objects to where you are shooting. That makes a huge difference as well.

 

[Guest]

All around performance and fit and finish, Donnyfl has my money. I am always willing to be persuaded for something better, but for aluminum and fit and finish and quality and of course sound reduction, I can’t find better. Plus he has always responded to my inquiries so he has a loyal customer for that too.

 

[Deepbass9]

All the testing I'd like to get to do myself...so glad there are folks with time to actually do some of it . Thanks for the read and info.

Snipe avg. value is a typo, BTW.

I'm a DFL fan, too. Replaced a 9" mod on my Sumatra with a Tatsu and it's still one of my quietest guns. No mod...well we all know what that sounds like.....

 

[scratchcoobster]

Thanks Deepbass9. that value should be 86.44. Appreciate your input. BTW, I see that my table got cut off and the last two moderators weren't displayed. They were both DonnyFLs. I will post them later.

 

[scratchcoobster]

I don't know what type of sound meter your using but most do not pick up Peak values. They just pick up an average which is not representative of what a person would hear. I use audyssey program on a PC 2 gauge relative loudness of the sounds. Since the microphone on a PC is crap you can assume it's not linear and it's loudness response and it isn't flat in his frequency response either. However it does pick up the actual sound waveform so you can pick up Peaks very easily and you can compare them against other tests. Unless you are testing in the middle of a desert then you have to consider attenuation and Reflections from nearby objects to where you are shooting. That makes a huge difference as well.

As it happens I WAS in the desert - New Mexico. Also was using a stand alone peak level sound meter (Omega) not Pc or phone mike. No reflections or attenuation,, as there is only sand and distant mountains here. no buildings,etc. This test was an attempt to get real data, not human hearing responses such as 'it sounded quieter', or 'It cut the sound in half, etc.

This is not a laboratory test. The purpose was to try to supply number values to compare the dampening effect of different moderators. These values can be compared and used as a guide, a seemingly reasonable purpose.

 

[Guest]

I don't know what type of sound meter your using but most do not pick up Peak values. They just pick up an average which is not representative of what a person would hear. I use audyssey program on a PC 2 gauge relative loudness of the sounds. Since the microphone on a PC is crap you can assume it's not linear and it's loudness response and it isn't flat in his frequency response either. However it does pick up the actual sound waveform so you can pick up Peaks very easily and you can compare them against other tests. Unless you are testing in the middle of a desert then you have to consider attenuation and Reflections from nearby objects to where you are shooting. That makes a huge difference as well.

As it happens I WAS in the desert - New Mexico. Also was using a stand alone peak level sound meter (Omega) not Pc or phone mike. No reflections or attenuation,, as there is only sand and distant mountains here. no buildings,etc. This test was an attempt to get real data, not human hearing responses such as 'it sounded quieter', or 'It cut the sound in half, etc.

This is not a laboratory test. The purpose was to try to supply number values to compare the dampening effect of different moderators. These values can be compared and used as a guide, a seemingly reasonable purpose.

Awesome +1

 

[fe7565]

Thanks for the tests. All the setup and ambient seems pretty scientific and accurate for me. Seems like that bigger is not always better. Because of the already low decibels of the Red Wolf, I would suggest the louder Brocock so there is more air pressure and turbulence to tame. The Red Wolf's shroud seemingly already does a good job at diffusing the exiting air before hitting the moderator area. With the louder base of 94.8 dB the performance of each moderator may be more apparent. 

 

[BlackICE]

https://www.omega.com/en-us/sensors-and-sensing-equipment/c/decible-meters

One of these. Peak sound readings aren't the same as fast response. Eg. if you have just 1 waveform at 10KHz at 100 db. Most meters won't pick up anything at all even using fast response, or may average that one waveform over a few milliseconds. Recording that actual waveform you will see the 1 wave. That said people can't hear 1 wave at 10KHz anyway. The desert is a great place to do such testing.

 

[tor47]

When I tried the DonnyFL tatsu on my impact, it was a lilte louder than the empty can, which also seems to be the case on the redwolf. I do not know if they would behave different on a unshrouded gun.

 

[Blackpaw]

I do appreciate the thoroughness or the testing. Also, my feeling is the more powerful the gun regardless of the caliber you get diminishing returns. Meaning the moderator can only be so affective. You’ve addressed this too but it applies to all machines there is a point where what you want out of it can only be pushed so far. 

 

[Smok3y]

The data you provided fits pretty well with the feedback I give people when they ask which is better. We all think that one is going to blow the others all away until we try a bunch, but it doesn’t happen most of the time. They often sound pretty dang close. 

 

[scratchcoobster]

Right on Smok3y, I found that the differences are minimal across size, volume, length, etc. (less than 1 dB) Like most things, it comes down to how the individual likes the look and feel more than the performance, or practicality. Somehow a well finished, nice looking moderator just sounds better than one that is not so sexy. Human nature.

 

[Clifton]

The FX mod does pretty good for the light weight and what isn't in it. Your testing and sharing of your data is much appreciated.

 

[MacGyver]

...Plus he has always responded to my inquiries so he has a loyal customer for that too.

AGREED!

 

[bigHUN]

Q:

Any air (blast) stripper in front of the moderator? Better if I would ask tuned stripper - muzzle break?

 

[JungleShooter]

Jack,

I just stumbled onto your moderator test. Excellent, THANK YOU for doing it and sharing your results with us!

I've started collecting silencer tests to get a better idea of their effectiveness under different conditions. Now I can add this to my Silencer Specs Table. Thanks for documenting so carefully the test conditions, excellent!

Matthias

 

[elh0102]

I gave up on trying to make any evaluation using the typical meters that are generally available and affordable, most are crap. The best test, shoot and listen. The absolute db value is often less meaningful than the actual profile of the sound. A shot at 80 db that sounds like a shot, is usually not as helpful as a shot at 85 db, that sounds like something else. 

 

[scratchcoobster]

You are correct @elh0102. It's all about the shooting environment and the type of sounds your particular gun gives off. Sound is a very subjective sense, some people can hear a pin drop and others can't hear their TVs blasting, or the gigantic rumble of the bass on the car stereos. As for backyard friendly, that depends on how sensitive your neighbors are.